1. Field of the Invention
The present invention relates to an automatic ion concentration analyzing apparatus for use in quantitative analysis of ion concentration in a sample liquid such as blood and urea. In the apparatus according to the invention, the quantitative analysis of ion concentration is performed with the aid of ion selective electrodes.
2. Description of the Related Art
In a conventional automatic ion concentration analyzing apparatus using ion selective electrodes as an ion concentration measuring element, a single ion selective electrode is used for measuring a concentration of a single kind of ion included in the sample. But, this apparatus has a drawback that an analyzing speed cannot be made fast due to the responding speed of the ion selective electrode. In order to increase the analyzing speed of the ion concentration, an improvement of the apparatus is suggested, in which a plurality of ion selective electrodes are used for measuring the concentration of a single kind of ion included in the sample to be measured. However, since a number of ion concentration measuring systems are required in the improvement of the apparatus, the size of the analyzing apparatus as a whole becomes great.
In Japanese Utility Model Publication No. 62-8523, such an ion concentration analyzing apparatus is disclosed that a plurality of ion concentration measuring cells each comprising an ion selective electrode are provided, but a calculating section for calculating the measuring results measured in the ion concentration measuring cells and a displaying section for displaying the measuring results are commonly used for the plurality of ion concentration measuring systems. That is to say, electric signals supplied from the plurality of ion concentration measuring cells are commonly processed in the commonly used calculating and displaying sections. In the apparatus disclosed in this Japanese Utility Model Publication, although a plurality of ion selective electrodes are used for measuring the concentration of the single kind of ion included in the sample to be measured, it is attempted to make the apparatus as a whole, small in size. However, in the ion concentration analyzing apparatus, the ion concentration measuring section occupies a large capacity and the mechanism is rather more complex than the calculating and displaying sections. That is to say, in the ion concentration measuring section of the apparatus, there are provided not only a plurality of sample suction nozzles but also a plurality of nozzle driving systems for moving the plurality of sample suction nozzles to sample pick up positions, where sample cups each containing a sample to be measured are fed to, and to a nozzle washing section. Further, it is necessary to provide a plurality of sample cup feeding systems for feeding the sample cups to the sample pick up positions. Therefore, the ion concentration analyzing apparatus using a plurality of ion selective electrodes could not help being large in size.